scholarly journals Production of Thin PbxSn1–xTe Films by “Hot Wall” Method for Creating IR-Photodetectors

2021 ◽  
Vol 20 (6) ◽  
pp. 482-486
Author(s):  
V. A. Ivanov ◽  
V. V. Krasovskii ◽  
V. F. Gremenok ◽  
L. I. Postnova
Keyword(s):  
Thin Films ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Lead Concentration ◽  
Columnar Structure ◽  
Unit Cell ◽  
Lead Content ◽  
Electrical Measurements ◽  
Mechanical Adhesion ◽  
Wall Method

Alloys of lead and tin telluride (PbxSn1–xTe) are materials with good thermoelectric properties, as well as semiconductors that can be used as long-wave infrared detectors. Polycrystalline telluride of PbxSn1–xTe (0.05 £ x £ 0.80) alloys has been synthesized by direct fusion technique. Thin films of these materials have been obtained by the hot wall method depositing Сorning 7059 on glass substrates at Tsub = (200–350) oC and vacuum of about 10–5 Torr. The microstructure of the films has been investigated by XRD, SEM and EDX methods. The X-ray spectra of thin films have been in satisfactorily agreement with the spectra of the powder target and indicated the absence of binary phases. The films have shown a natural cubic crystalline structure. While increasing the lead content, the unit cell parameter of the crystal also increases. The established linear relationship between the unit cell parameter and the elemental composition corresponds to Vegard's law. The SEM analysis has shown that the films are polycrystalline, have a columnar structure, are tightly packed and have good mechanical adhesion. The grain size depends on the chemical composition and temperature of the substrate. The electrical measurements have shown that the grown films are non-degenerate semiconductors of p-type conductivity. The conductivity of the films was in the range of σ = (3 × 101)–(1 × 104) Ω–1×cm–1. An increase of lead concentration leads to a decrease in electrical conductivity. Hall mobility in the grown thin films increases in the range of changes in the lead content from ~10 to ~23 at. %, and decreases with a further increase to ~33 at. %. At the same time, the strongest dependence of the decrease in mobility on an increase in temperature increase is observed for films with a high lead content and is explained by the predominant scattering of charge carriers by vibrations of the crystal lattice. For a sample with an average lead concentration, an alternative effect of two scattering mechanisms is observed in the temperature dependence of the mobility: by impurity ions and by phonons.

Powder X-Ray Diffraction Data of Magnesium-Chlorophoenicite

1987 ◽  
Vol 2 (4) ◽  
pp. 225-226
Author(s):  
Peter Bayliss ◽  
Slade St. J. Warne
Keyword(s):  
New Jersey ◽  
Unit Cell Parameter ◽  
Diffraction Data ◽  
Cell Parameter ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Image Position

AbstractMagnesium-chlorophoenicite may be differentiated from the Mn-analogue chlorophoenicite, because for magnesium-chlorophoenicite at 7Å, whereas for chlorophoenicite.In a review of the literature for the Mineral Powder Diffraction File by Bayliss et al. (1980), powder X-ray diffraction data could not be found of the mineral species magnesium-chlorophoenicite, (Mg,Mn)3Zn2(AsO4)(OH,O)6. Dunn (1981) states that the powder X-ray diffraction data of magnesium-chlorophoenicite is essentially identical to that of chlorophoenicite (Mn analogue) and confirms that the minerals are isostructural.With the crystal structure parameters determined by Moore (1968) for a Harvard University specimen from New Jersey of chlorophoenicite, a powder X-ray diffraction pattern was calculated with the programme of Langhof, Physikalische Chemie Institute, Darmstadt. The calculated pattern was used to correct and complete the indexing of the powder X-ray diffraction data of chlorophoenicite specimen ROM M15667 from Franklin, Sussex County, New Jersey, U.S.A. by the Royal Ontario Museum (PDF 25-1159). With the correctly indexed data of ROM M15667, the unitcell parameters were refined by least-squares analysis and are listed in Table 1.The most magnesium-rich magnesium-chlorophoenicite found in the literature is a description of Harvard University specimen 92803 from Franklin, Sussex County, New Jersey, U.S.A. by Dunn (1981), where Mg is slightly greater than Mn. A 114.6 mm Debye-Schemer film taken of HU92803 with Cu radiation and a Ni filter (CuKα = 1.5418Å) was obtained from Dr. P. Dunn and measured visually. The unit-cell parameters, which were refined by least-squares analysis starting from the unit-cell parameters of PDF 25-1159 in space group C2/m(#12), are listed in Table 1, and give F28 = 4.1(0.050,136) by the method of Smith & Snyder (1979).The hkl, dcalulated, dobserved and relative intensities (I/I1) of HU92803 are presented in Table 2. With the atomic positions and temperature factors of chlorophoenicite determined by Moore (1968), the Mn atomic positions occupied by 50% Mg and 50% Mn, and the unit-cell parameters of HU92803, a powder X-ray diffraction pattern was calculated and Icalculated is recorded in Table 2. A third powder X-ray diffraction pattern was calculated with the Mn atomic positions fully occupied by Mg. Because the atomic scattering factor of Mn is more than twice greater than Mg, chlorophoenicite may be differentiated from magnesium-chlorophoenicite based upon the calculated intensities of the first three reflections given in Table 3.Although the a, c and β unit-cell parameters of chlorphoenicite are similar to those of magnesium-chlorphoenicite, the b unit-cell parameter of chlorophoenicite is significantly greater than that of magnesium-chlorophoenicite (Table 1). The b unit-cell parameter represents the 0–0 distance of the Mn octahedra (Moore, 1968). Since the size of Mn is greater than that of Mg, chlorophoenicite may be differentiated from magnesium-chlorophoenicite based upon the b unit-cell parameter given in Table 1.American Museum of Natural History (New York, N.Y., U.S.A.) specimen 28942 from Sterling Hill, Ogdensburg, New Jersey is composed of willemite, haidingerite and magnesian chlorophoenicite. A spectrographic analysis of the magnesian chlorophoenicite shows As, Mg, Mn and Zn. Powder X-ray diffraction data (PDF 34-190) of the magnesian chlorophoenicite was collected by diffractometer with Cu radiation and a graphite 0002 monochromator (Kα1 = 1.5405) at a scanning speed of 0.125° 2θ per minute. The unit-cell parameters, which were refined by leastsquares analysis starting from the unit-cell parameters of PDF 25-1159, are given in Table 1. Specimen AM 28942 is called chlorophoenicite, because of its large b unit-cell parameter (Table 1), and the I/I1 of 25 for reflection 001 and of 50 for reflection 201 compared to the Icalculated in Table 3.

Least-squares refinement of biaxial stress components and unit-cell parameter in a 〈111〉 textured cubic TiN polycrystalline thin film by X-ray diffraction

2010 ◽  
Vol 25 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Ryouichi Yokoyama ◽  
Jimpei Harada ◽  
Yoshiaki Akiniwa
Keyword(s):  
Thin Film ◽  
Least Squares ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Unit Cell ◽  
Biaxial Stress ◽  
X Ray Diffraction ◽  
Polycrystalline Thin Film ◽  
Tin Film ◽  
Stress Components

Biaxial residual stress in a 〈111〉 textured cubic TiN polycrystalline thin film was analyzed by linear least-squares refinement using the method proposed by Yokoyama and Harada [J. Appl. Crystallogr. 42, 185–191 (2009)]. Values of the unstressed (or stress-free) unit-cell parameter a0=4.2332±0.0006 Å and the stress components of σ11=397(88), σ22=401(88), and σ12=−110(100) were obtained. The values of the in-plane stresses σ11 and σ22 presented in the TiN film are practically the same, while σ12 is relatively small. The results obtained in this study confirm that the above theoretical prediction by Yokoyama and Harada can be used to obtain reliable values of stress-free unit-cell parameter and three biaxial stress components of a textured cubic thin film.

About the crystal structure of La1−xSrxCoO3−δ (0≤x≤0.6)

1996 ◽  
Vol 11 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Nicole M. L. N. P. Closset ◽  
René H. E. van Doorn ◽  
Henk Kruidhof ◽  
Jaap Boeijsma
Keyword(s):  
Crystal Structure ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

The crystal structure of La1−xSrxCoO3−δ (0≤x≤0.6) has been studied, using powder X-Ray diffraction. The crystal structure shows a transition from rhombohedral distorted perovskite for LaCoO3−δ into cubic perovskite for La0.4Sr0.6CoO3−δ. The cubic unit cell parameter is ac=3.8342(1) Å for La0.4Sr0.6CoO3−δ, the space group probably being Pm3m. Using a hexagonal setting, the cell parameters for La0.5Sr0.5CoO3−δ, are a=5.4300(3) Å, c=13.2516(10) Å; a=5.4375(1) Å, c=13.2313(4) Å for La0.6Sr0.4CoO3−δ; a=5.4437(1) Å, c=13.2085(5) Å for La0.7Sr0.3CoO3−δ; a=5.4497(2) Å, c=13.1781(6) Å for La0.8Sr0.2CoO3−δ and a=5.4445(2) Å, c=13.0936(6) Å for LaCoO3−δ with the space group probably being R3c.

High-temperature powder x-ray diffraction of yttria to melting point

1999 ◽  
Vol 14 (2) ◽  
pp. 456-459 ◽  
Author(s):  
V. Swamy ◽  
N. A. Dubrovinskaya ◽  
L. S. Dubrovinsky
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Melting Point ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Unit Cell ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
Thermal Expansion Data ◽  
X Ray

Powder x-ray diffraction data of yttria (Y2O3) were obtained from room temperature to melting point with the thin wire resistance heating technique. A solid-state phase transition was observed at 2512 ± 25 K and melting of the high-uemperature phase at 2705 ± 25 K. Thermal expansion data for α–Y2O3 (C-type) are given for the range 298–2540 K. The unit cell parameter increases nonlinearly, especially just before the solid-state transition. The x-ray diffraction spectrum of the high-temperature phase is consistent with the fluorite-type structure (space group Fm3) with a refined unit cell parameter a = 5.3903(6) Å at 2530 K. The sample recrystallized rapidly above 2540 K, and above 2730 K, all the diffraction lines and spots disappeared from the x-ray diffraction spectrum that suggests complete melting.

Structure of Yttrium Aluminium Garnet Obtained by the Glycothermal Method

2006 ◽  
Vol 45 ◽  
pp. 691-696 ◽  
Author(s):  
Saburo Hosokawa ◽  
Yusuke Tanaka ◽  
Shinji Iwamoto ◽  
Masashi Inoue
Keyword(s):  
Unit Cell Parameter ◽  
Single Phase ◽  
Cell Parameter ◽  
Rietveld Analysis ◽  
Exothermic Peak ◽  
Unit Cell ◽  
Yttrium Aluminium Garnet ◽  
Stoichiometric Mixture ◽  
Aluminium Isopropoxide ◽  
Yttrium Aluminium

The reaction of a stoichiometric mixture of aluminium isopropoxide and yttrium acetate in 1,4-butanediol (1,4-BG) at 300 °C directly yielded crystalline yttrium aluminium garnet (YAG), while the reaction in ethylene glycol (EG) afforded an amorphous product in which a large amount of EG moieties remained. The latter product exhibited an exothermic peak due to the crystallization of YAG at around 900 °C and single-phase YAG was obtained by calcination at 1000 °C. The YAG sample directly obatained in 1,4-BG had a large unit cell parameter (12.144 Å), whereas the YAG sample obtained by the latter method had a unit cell parameter (12.015 Å) essentially identical with the value (12.01 Å) reported in the JCPDS card. Rietveld analysis indicates that the former crystals had Al vacancies at 24d sites and oxygen vacancies while the latter was essentially free from these vacancies.

Synthesis and Unit Cell Parameter Refinement of 25 Tungsten Bronze Ferroelectrics

1988 ◽  
Vol 3 (4) ◽  
pp. 222-233 ◽  
Author(s):  
Lauren A. Zellmer ◽  
Deane K. Smith ◽  
Diane Nelson ◽  
Barry E. Scheetz
Keyword(s):  
Solid State ◽  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Tungsten Bronze ◽  
Unit Cell ◽  
Chemical Formula ◽  
Tungsten Bronze Structure ◽  
Cell Parameters ◽  
General Chemical ◽  
Solid State Sintering

AbstractSynthesis and unit cell parameter refinement of 25 ferroelectric compounds with the tungsten bronze structure are reported. A general chemical formula for these compounds is (A1, A2, C) B10 O30, where specifically A1 and A2 = K, Na, Ba, Sr, Pb, La, Eu, Sm, Y, Bi; C = Li; and B = Nb, Ta, Ti, W. All compounds were prepared by solid state sintering at temperatures ranging from 1100°C to 1380°C. Refined cell parameters (tetragonal with space group P4bm[100]), I/Icor values, calculated densities and Z values are included for the 25 compounds.

Sign in / Sign up

Export Citation Format

Share Document